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Mon, 02 Mar 2015 23:43:44 +0000en-UShourly1http://wordpress.org/?v=4.1.1Image Gallery: mystery bright spots on Cereshttp://themeridianijournal.com/2015/03/image-gallery-mystery-bright-spots-on-ceres/
http://themeridianijournal.com/2015/03/image-gallery-mystery-bright-spots-on-ceres/#commentsMon, 02 Mar 2015 03:31:54 +0000http://themeridianijournal.com/?p=5414The Dawn spacecraft has almost reached the dwarf planet Ceres, and a lot more detail can be seen as it gets closer. The odd bright spots which have puzzled scientists for a long time now can also be seen more clearly for the first time. What was thought to be one spot in this crater […]

The Dawn spacecraft has almost reached the dwarf planet Ceres, and a lot more detail can be seen as it gets closer. The odd bright spots which have puzzled scientists for a long time now can also be seen more clearly for the first time. What was thought to be one spot in this crater is now obviously two close together. Are they exposed ice or some other material? Are they related to possible cryovolcanoes? Dawn was 46,000 kilometers (29,000 miles) away when it took this image on February 18, 2015.

Dawn will arrive at Ceres on March 6, and we will then have the first close-up images of this still-unexplored world. There will also be a NASA press conference tomorrow, March 2 at 9:00 am PT (12:00 pm ET) to discuss the arrival of Dawn at Ceres.

]]>http://themeridianijournal.com/2015/03/image-gallery-mystery-bright-spots-on-ceres/feed/0Scientists debate how to search for life on Europa in new missionhttp://themeridianijournal.com/2015/02/scientists-debate-how-to-search-for-life-on-europa-in-new-mission/
http://themeridianijournal.com/2015/02/scientists-debate-how-to-search-for-life-on-europa-in-new-mission/#commentsSat, 28 Feb 2015 00:17:57 +0000http://themeridianijournal.com/?p=5409Jupiter’s moon Europa, with its subsurface ocean, is considered by many to be the best place in the Solar System to search for extraterrestrial life. With NASA now committing itself to a new mission sometime in the 2020s, the focus is turning to what would be the best strategy for looking for any life which […]

]]>Jupiter’s ice-covered moon Europa hides a water ocean beneath its surface. A return mission is now planned to help search for evidence of life there. Photo Credit: NASA/JPL

Jupiter’s moon Europa, with its subsurface ocean, is considered by many to be the best place in the Solar System to search for extraterrestrial life. With NASA now committing itself to a new mission sometime in the 2020s, the focus is turning to what would be the best strategy for looking for any life which may be there. Over 200 scientists and engineers met at NASA’s Ames Research Center in Mountain View, Calif., last week for a workshop called the The Potential for Finding Life in a Europa Plume to do just that.

As NASA science administrator John Grunsfeld told the meeting: “We’re going to do a Europa mission. If there’s something trapped in that water, and we potentially have the opportunity to see it, it could be transformative.”

Europa may have geysers of water vapor erupting from the ocean below, as in this artist’s conception. If so, they could be sampled and analyzed for possible evidence of life. Image Credit: NASA/ESA/K. Retherford/SWRI

Indeed. Many people, scientists, and non-scientists alike have been calling for a new mission to Europa. Now that NASA itself is willing to do it, the question is how to search for evidence of life. Ambitious ideas have included landers and eventually a probe that could penetrate the ice shell covering the ocean and enter the water itself. Such technically advanced missions are still quite a ways off, but in the meantime the idea of an orbiter gained ground, or at least a probe which could make repeated flybys of the moon.

Along this line of thought, the Europa Clipper concept was born. Due to the very high radiation in this region around Europa and Jupiter, the probe wouldn’t remain in orbit, but rather make repeated close flybys of Europa. Clipper would study Europa’s surface and interior to better understand the geological structure of the moon and the composition of the ocean. It would be difficult to search for life itself this way, but much could be learned about the potential habitability of Europa, similar to how the current Mars rovers are focusing on determining past habitability rather than looking for life itself.

While that would be exciting in its own right, the big question is still whether Europa could be hosting life of some kind now. Europa is a long way away, much farther than Mars, so it would seem expedient that if you are going to go all the way back there again, then at least some kind of life-search capabilities should be included in the design of the probe.

Hubble Space Telescope image of Europa showing area where water vapor was detected emanating from the surface in 2013. Image Credit: NASA/ESA/L. Roth/SWRI/University of Cologne

A discovery made in 2013 by the Hubble Space Telescope may make it easier for scientists to do just that: huge plumes of water vapor were reported coming from Europa’s surface. Was Europa venting its water similar to how Saturn’s moon Enceladus does? If so, then a probe could fly through them and sample them, just like the Cassini spacecraft has already done with Enceladus’ water vapor geysers. That would be a much easier way to analyze what is in the water coming up to the surface from below. Indeed, Cassini’s analysis of Enceladus’ plumes has already found water vapor, ice particles, salts, and organics. Cassini isn’t equipped, however, to detect life itself, such as bacteria.

The only problem with this is that since then, Europa’s plumes haven’t been seen again. This suggests that they may be sporadic or perhaps not even really there after all. But if they are and can be confirmed, they would provide an ideal way for a probe such as Europa Clipper to look for traces of life without having to land or bore through the ice.

Mass spectrometry could be used to look for complex chemicals which might indicate life processes. Even if living cells such as bacteria died while being injected into space, they could still be identified. “Death is just another form of life,” as planetary scientist Chris McKay noted.

Even antibodies might be useful, as they could be attached to a chip, grabbing any organic particles for analysis by other instruments on the spacecraft, McKay suggested.

The Europa Clipper concept mission. The probe would make repeated flybys of Europa, studying its surface and interior. Image Credit: NASA/JPL-Caltech

So what else could be done if the plumes are not seen again? One idea, from Charles Hibbitts of Johns Hopkins University in Baltimore, Md., is to punch into the surface ice. A precision projectile would be shot into the ice from a probe, similar to how the Deep Impact mission sent a small projectile smashing into the surface of a comet in 2005. Material in the resulting plume could then be collected and analyzed by the probe. Since the surface ice crust is thought to be several miles thick in most places, the projectile wouldn’t hit the ocean itself, but could still allow scientists the ability to examine the composition of the ice itself. There are, however, also thought to be smaller lakes of water within the ice crust, closer to the surface. If such a spot could be found, a projectile could be aimed there, offering perhaps a better chance of finding material from, or at least closer to, a body of liquid water.

Tiny satellites like cubesats are another possibility, as suggested by David Mauro of NASA Ames. Two small satellites, together called Europa Plume Chaser, would be sent to Jupiter with cameras and miniaturized instruments. One probe would search for plumes, while the other would actually fly through them and analyze them. Such a mission might be more cost effective, if the plumes can be verified.

The mantra for the search for life elsewhere has long been “follow the water.” Europa provides an unique opportunity to do that, along with some other moons like Enceladus. Now that there is finally a firm commitment to returning to Europa, the mission needs to actually move forward, and the sooner the better, since it takes several years just to get there, even with the fastest rockets. “The clock is ticking,” Grunsfeld said. “I just hope we don’t miss this remarkable opportunity.”

]]>http://themeridianijournal.com/2015/02/scientists-debate-how-to-search-for-life-on-europa-in-new-mission/feed/0Getting closer! New Horizons sees two of Pluto’s smaller moons for first timehttp://themeridianijournal.com/2015/02/getting-closer-new-horizons-sees-two-of-plutos-smaller-moons-for-first-time/
http://themeridianijournal.com/2015/02/getting-closer-new-horizons-sees-two-of-plutos-smaller-moons-for-first-time/#commentsSun, 22 Feb 2015 04:39:34 +0000http://themeridianijournal.com/?p=5388The New Horizons spacecraft, on course for a historic encounter with Pluto this summer, is now close enough to see two of its smaller moons for the first time. The new views also come 85 years after the discovery of Pluto by astronomer Clyde Tombaugh on Feb. 18, 1930. The images were taken between Jan. […]

The New Horizons spacecraft, on course for a historic encounter with Pluto this summer, is now close enough to see two of its smaller moons for the first time. The new views also come 85 years after the discovery of Pluto by astronomer Clyde Tombaugh on Feb. 18, 1930.

The images were taken between Jan. 27 and Feb. 8, 2015, at distances ranging from about 125 million to 115 million miles (201 million to 186 million kilometers), and for the first time show the tiny moons Nix and Hydra, which are much smaller than Pluto’s largest moon, Charon. They are the first of a series of long-exposure images that will be taken until early March, which will allow the New Horizons team to refine the moons’ orbits ahead of the encounter on July 14.

“Professor Tombaugh’s discovery of Pluto was far ahead its time, heralding the discovery of the Kuiper Belt and a new class of planet,” said Alan Stern, the principal investigator for New Horizons from Southwest Research Institute, Boulder, Colo. “The New Horizons team salutes his historic accomplishment.”

As New Horizons science team member John Spencer, also from Southwest Research Institute, noted: “It’s thrilling to watch the details of the Pluto system emerge as we close the distance to the spacecraft’s July 14 encounter. This first good view of Nix and Hydra marks another major milestone, and a perfect way to celebrate the anniversary of Pluto’s discovery.”

In the right-hand versions of the images, the glare from Pluto, Charon, and background stars has been mostly removed in order to see Nix and Hydra more clearly. The blotchy and streaky features are not real, just artifacts of the image processing.

The images were also assembled into a seven-frame movie, showing Nix and Hydra moving in their orbits around Pluto. Each frame is a combination of five 10-second images, taken with the Long-Range Reconnaissance Imager (LORRI) instrument on New Horizons.

Nix and Hydra were first discovered in images taken by the Hubble Space Telescope in 2005. Hydra is the outermost known moon of Pluto, and orbits every 38 days at a distance of 40,200 miles (64,700 kilometers). Nix orbits every 25 days at a distance of 30,260 miles (48,700 kilometers). Both moons are tiny, between 25-95 miles (40-150 kilometers) in diameter, but more accurate measurements won’t be possible until New Horizons gets closer.

There are at least two other moons, Styx and Kerberos, which are even smaller and too faint still to be seen by New Horizons at this distance.

Since Pluto is so small itself, being classified as a dwarf planet, it was a surprise to find that it has at least five moons orbiting it. There may even be others, still as yet undetected. Even Mars, which is much larger than Pluto, only has two tiny asteroid-sized moons, Phobos and Deimos. And Earth, of course, has only one moon. Venus and Mercury have none.

Some astronomers think that Pluto may also have faint rings, but this won’t be able to be confirmed, or refuted, until New Horizons gets much closer this summer. It is also possible that Pluto and Charon uniquely share the same atmosphere, as tenuous as it is. That atmosphere may sublimate and condense between the two bodies in an ever-repeating cycle depending on the season and amount of sunlight. It is even thought that Pluto or Charon may have an interior ocean of water, or at least used to, similar to Europa or Enceladus. Even with the little that is known to date, astronomers are certain that Pluto and its moons are more active and intriguing than used to be thought possible.

New Horizons had also recently sent back its best images of Pluto so far, the first of many to come as the spacecraft approaches the dwarf planet. They will continue to only get better from now on, and soon they will surpass the best images taken by the Hubble Space Telescope. In those images, Pluto and its moons look like little more than bright dots of light. Faint features can just be seen on Pluto’s surface, but nothing more.

That will all change this summer, however, when New Horizons conducts the first-ever flyby of this remote and fascinating little world. That tiny point of light will finally become a real place, never before seen up close until now.

]]>http://themeridianijournal.com/2015/02/getting-closer-new-horizons-sees-two-of-plutos-smaller-moons-for-first-time/feed/1Exploring an alien sea: NASA designs submarine to send to Titanhttp://themeridianijournal.com/2015/02/exploring-an-alien-sea-nasa-designs-submarine-to-send-to-titan/
http://themeridianijournal.com/2015/02/exploring-an-alien-sea-nasa-designs-submarine-to-send-to-titan/#commentsSat, 21 Feb 2015 20:23:54 +0000http://themeridianijournal.com/?p=5375Who wouldn’t want to go explore an alien sea? It seems that NASA would certainly like to, and the agency has unveiled a new submarine design to hopefully do just that one day. The submarine would be sent to Saturn’s largest moon, Titan, to dive into one of the large liquid methane seas on the […]

]]>Artist’s conception of the Titan Submarine Phase I Conceptual Design. Much like submarines on Earth, the sub would explore the depths of one of Titan’s methane/ethane seas. Image Credit: NASA

Who wouldn’t want to go explore an alien sea? It seems that NASA would certainly like to, and the agency has unveiled a new submarine design to hopefully do just that one day. The submarine would be sent to Saturn’s largest moon, Titan, to dive into one of the large liquid methane seas on the moon’s frigid surface; such a mission idea may sound like science fiction, but it’s not, and would be the first ever to explore a sea on another world which is both Earth-like in some ways, yet utterly alien in others.

The submarine design, called the Titan Submarine Phase I Conceptual Design, was presented at the Innovative Advanced Concepts (NIAC) Symposium in Cocoa Beach, Fla., and is essentially a submersible robot that could explore the liquid methane/ethane seas and lakes on Titan much the same way a submarine works on Earth. It was created by NASA Glenn’s COMPASS Team along with other researchers from Applied Research Lab. Appearance-wise, it resembles some older submarine models, but the technology involved would be much more advanced, necessary for working in such a cold, dark environment.

The submarine would use a large dorsal phased array antenna, but in order to communicate back to Earth, it would need to resurface for an estimated 16 hours each time and could use a radiothermal Stirling generator for propulsion. It would, however, also have to be highly autonomous to work on its own at such a far distance from Earth. To prevent freezing in the extreme cold, a special piston-driven type of system would need to be developed as well. The submarine would weigh about 2,200 lb (one tonne). As for speed, NASA estimated the sub could travel at about 2.2 mph (3.6 km/h). The submarine would also likely use ballast tanks like subs on Earth, but they would have to be designed to work in liquid methane/ethane instead of water.

The most likely destination for the submarine would be the largest sea on Titan, Kraken Mare. Image Credit: NASA

The submarine would be delivered to Titan’s surface using a winged spacecraft similar to a U.S. Air Force X-37. The spacecraft would ditch and then sink, leaving the vessel floating on the surface of the sea.

There are several seas and many smaller lakes on Titan, so where to send the sub? The most likely location is the sea called Kraken Mare, which is also the largest. It covers approximately 154,000 square miles, with the depth estimated to be as much as 525 feet (some estimates say perhaps up to 1,000 feet deep). Kraken Mare in the Titanian arctic, between 60 and 80 degrees north latitude. The submarine would be designed for a 90-day mission covering 1,240 miles of the sea. From the paper:

“The vehicle would observe – and perhaps ultimately exploit – tidal currents in the sea, which follow a cycle once per Titan day, or 16 Earth days. When surfaced, as well as communicating with Earth, the vehicle would use a mast-mounted camera to observe the sea state and shoreline landscape, and would record meteorological observations. Measurement of the trace organic components of the sea, which perhaps may exhibit prebiotic chemical evolution, will be an important objective, and a benthic sampler would acquire and analyze sediment from the seabed. These measurements, and seafloor morphology via sidescan sonar, may shed light on the historical cycles of filling and drying of Titan’s seas. Models suggest Titan’s active hydrological cycle may cause the north part of Kraken to be ‘fresher’ (more methane-rich) than the south, and the submarine’s long traverse will explore these composition variations.”

Like with any good submarine, there would of course be a mast camera, for observing the surrounding environment. As noted by NASA scientists, a possible bonus of that is if there were breaks in the near-perpetual cloud cover, the submarine could get a glimpse of Saturn from Titan’s surface, something dreamed about and depicted in space artwork for decades. That view would be unprecedented, with the sea surrounding the sub and Saturn looming large in the sky overhead. A surreal scene, yet also very real at the same time.

The Titan submarine would use side-scanning sonar to assist in its exploration of the Kraken Mare sea. Image Credit: NASA

The primary objectives of the mission would be wide-ranging, including studying the chemical makeup of the liquid and sediment at the bottom of the sea. It is already known that Titan’s atmosphere and surface are rich in organic compounds, so they would also be searched for in the sea. From the paper:

“Measurement of the trace organic components of the sea, which perhaps may exhibit prebiotic chemical evolution, will be an important objective, and a benthic sampler (a robotic grabber to sample sediment) would acquire and analyze sediment from the seabed. These measurements, and seafloor morphology via sidescan sonar, may shed light on the historical cycles of filling and drying of Titan’s seas. Models suggest Titan’s active hydrological cycle may cause the north part of Kraken to be ‘fresher’ (more methane-rich) than the south, and the submarine’s long traverse will explore these composition variations.”

If there were breaks in Titan’s clouds, the submarine could view Saturn looming large in the sky above. Image Credit: NASA

Such a mission could be ready by about 2040, so still a ways off yet, and, as usual, dependent on funding. The fact that the concept is now being designed, however, is exciting, and it would be the first of its kind. Until now, planetary missions, including to moons, have been limited to orbiters, landers, and rovers.

Of course, there is also that other big question: What about life? Although Titan’s seas are much colder than any on Earth (about -298 degrees Fahrenheit), some scientists think that there could still possibly be primitive forms of life in them, perhaps similar to some organisms (methanotrophs) on Earth which consume methane for energy, since Titan’s atmosphere contains an abundance of methane, as well as nitrogen. Even if no life itself is present, it is thought that Titan represents what conditions might have been like on Earth much earlier in its history, including pre-biotic processes which led to the development of life on our own planet.

Titan is the only other place in the Solar System known to have bodies of liquid on its surface. There are also rivers and rainfall of liquid methane/ethane. The process is like a colder version of Earth’s hydrological cycle; it resembles Earth’s in many ways, yet is also distinctly alien. There may also be a subsurface ocean of water, similar to moons like Europa and Enceladus. It is likely deep underground, however, so exploring it probably won’t be feasible in the near future.

Diving into one of Titan’s seas is one of the most exciting possibilities in planetary exploration, and this new concept design is a big step closer to making it a reality.

See the published paper for more details about the design concept. More information about Cassini and Titan is available here.

]]>Radar view of Ligeia Mare, a large hydrocarbon sea on Titan. The original version is on the left and the enhanced, “despeckled” version is on the right. Image Credit: NASA/JPL-Caltech/ASI

Saturn’s largest moon Titan is a fascinating world, uniquely alien yet eerily Earth-like in many ways, with its rain, rivers, lakes, seas, and massive sand dunes. But in this extremely cold environment, it is liquid methane and ethane which act as “water,” mimicking the hydrological cycle on Earth. Also, due to the perpetual and global hazy cloud cover, the only way to see these features from orbit is by using radar, which is what the Cassini spacecraft has done on a regular basis for quite a few years now. As good as they are, though, the radar images contain electronic noise, which reduces sharpness and clarity. But now a new technique is letting planetary scientists see Titan’s surface more clearly than ever before.

A perspective radar view of the eastern shoreline of Kraken Mare, another large hydrocarbon sea on Titan. The image has been despeckled to bring out more detail in the surface features. Image Credit: Credit: NASA/JPL-Caltech/ASI

The technique is referred to as “despeckling” and produces cleaner images than the original radar images from the Cassini Synthetic Aperture Radar (SAR) instrument on Cassini. It uses an algorithm to modify the noise in the images, making it easier to see small-scale features or changes in the landscape. The idea was initiated by Antoine Lucas while he was working with members of the Cassini imaging team. He was a postdoctoral researcher at the California Institute of Technology in Pasadena at the time.

“Noise in the images gave me headaches,” said Lucas. Understandable, as it can make the images more difficult to interpret and, of course, just makes them less clear than they could be. But now, Lucas said, “My headaches were gone, and more importantly, we were able to go further in our understanding of Titan’s surface using the new technique.”

According to Randy Kirk, a Cassini radar team member from the U.S. Geologic Survey in Flagstaff, Ariz., “This is an amazing technique, and Antoine has done a great job of showing that we can trust it not to put features into the images that aren’t really there. It takes a lot of computation, and at the moment quite a bit of ‘fine-tuning’ to get the best results with each new image, so for now we’ll likely be despeckling only the most important – or most puzzling – images.”

It is thought that the speckle noise itself, when analyzed separately, might be useful, providing clues about the surface and even the subsurface of Titan.

Scientists can also now produce better 3-D digital elevation maps of Titan’s surface, as well as seeing sea and lake shorelines, river channels, and dunes in greater detail.

“This new technique provides a fresh look at the data, which helps us better understand the original images,” said Stephen Wall, deputy team lead of Cassini’s radar team, based at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “With this innovative new tool, we will look for details that help us to distinguish among the different processes that shape Titan’s surface,” he added.

As seen by regular cameras or the human eye, Titan appears almost featureless due to the thick haze which envelopes the moon’s atmosphere and obscures the surface. Photo Credit: NASA/JPL-Caltech

While getting a better look at surface features in general, the technique could also help to solve some Titanian mysteries such as the “magic islands” in some of the seas which seem to appear and disappear at different times. Puzzling features like these only make Titan even more enticing to scientists. There is also thought to be a subsurface ocean of water, similar to moons like Europa and Enceladus. With an atmosphere rich in organic compounds, some scientists have even suggested that some form of primitive life might exist in the hydrocarbon seas and lakes, despite the bitter cold.

Titan is a complex world, with hydrological and geological processes that scientists are just beginning to explore and understand. Concepts for more advanced future landers, or even a boat or submarine to explore a Titanian sea, are being designed, even if still uncertain when they may ever launch. Exciting, but until then these enhanced images (and ones from the Huygens lander in 2005) will help to better show Titan as the incredible world that it really is.

Information about the new technique was published recently in the Journal of Geophysical Research: Planets.

]]>http://themeridianijournal.com/2015/02/new-technique-provides-better-clearer-radar-images-of-titans-amazing-surface/feed/0Cassini data indicates Enceladus’ ocean similar to soda lakes on Earthhttp://themeridianijournal.com/2015/02/cassini-data-indicates-enceladus-ocean-similar-to-soda-lakes-on-earth/
http://themeridianijournal.com/2015/02/cassini-data-indicates-enceladus-ocean-similar-to-soda-lakes-on-earth/#commentsFri, 20 Feb 2015 23:56:21 +0000http://themeridianijournal.com/?p=5356Along with Jupiter’s infamous moon Europa, Saturn’s moon Enceladus is one of the most fascinating places in the Solar System, with its huge geysers of water vapour erupting from cracks in the surface at the south pole. The massive plumes are now thought to originate in a subsurface ocean or sea of salty liquid water, […]

]]>The geysers of Enceladus, erupting through cracks in the ice at the south pole from a subsurface salty ocean or sea. Image Credit: NASA/JPL

Along with Jupiter’s infamous moon Europa, Saturn’s moon Enceladus is one of the most fascinating places in the Solar System, with its huge geysers of water vapour erupting from cracks in the surface at the south pole. The massive plumes are now thought to originate in a subsurface ocean or sea of salty liquid water, similar perhaps to Europa’s underground ocean. Now, new analysis is providing a more detailed look at the chemical makeup of this unique alien environment and its potential to support life.

The Cassini spacecraft orbiting Saturn has made many close flybys of this intriguing moon, including directly through some of the saltwater spray in the plumes themselves (over 100 individual plumes counted to date), “tasting” them as it did so. So far, scientists know that the plumes contain water vapor, ice particles, salts, and organic material. This has already shown that the water below is similar in ways to the water in oceans on Earth. Needless to say, this has caused some excitement among planetary scientists, and the public as well, as it presents the possibility of some form of life existing in the Enceladian ocean. Cassini itself can’t confirm or deny that, but it can provide important clues as to the actual conditions in this strange environment and whether they could support life.

As it turns out, they could, although the ocean may be more salty than most ocean life on Earth is used to. From the press release:

“The model indicates that Enceladus’ ocean is a Na-Cl-CO3 solution with an alkaline pH of ~11-12. The dominance of aqueous NaCl is a feature that Enceladus’ ocean shares with terrestrial seawater, but the ubiquity of dissolved Na2CO3 suggests that soda lakes are more analogous to the Enceladus ocean.”

Basically, the water contains a lot of dissolved sodium carbonate (Na2CO3), a sodium salt. The pH level is higher than usual, about 11-12 (seawater on Earth is typically about 8.08 to 8.33). So, if as indicated by these preliminary studies, the water inside Enceladus is similar to soda lakes on Earth, which are highly alkaline (very salty).

Diagram showing the interior of Enceladus as currently understood. Image Credit: NASA/JPL-Caltech/SSI

This may sound like a rather inhospitable environment, but at least on Earth, that is not true. Such high-salinity soda lakes host complex ecosystems with a rich variety of prokaryotes (bacteria and archaeabacteria), eukaryotic algae, protists, and fungi. Brine shrimp and fish have also been found in some of the lesser alkaline soda lakes. Some species, known as alkaliphiles, have adapted specifically to the soda lakes and would be unable to live in a more neutral-pH environment. From the published paper:

“Knowledge of the pH dramatically improves our understanding of geochemical processes in Enceladus’ ocean. In particular, the high pH is interpreted to be a key consequence of serpentinization of chondritic rock, as predicted by prior geochemical reaction path models, although degassing of CO2 from the ocean may also play a role depending on the efficiency of mixing processes in the ocean. Serpentinization inevitably leads to the generation of H2, a geochemical fuel that can support both abiotic and biological synthesis of organic molecules such as those that have been detected in Enceladus’ plume.

Mono Lake in California, a high-alkaline soda lake. Tufa towers of calcium carbonate have formed from the interaction of freshwater springs and alkaline lake water. Photo Credit: Brocken Inaglory/Wikimedia Commons

Serpentinization and H2 generation should have occurred on Enceladus, like on the parent bodies of aqueously altered meteorites; but it is unknown whether these critical processes are still taking place, or if Enceladus’ rocky core has been completely altered by past hydrothermal activity. The presence of native H2 in the plume would provide strong evidence for contemporary aqueous alteration. The high pH also suggests that the delivery of oxidants from the surface to the ocean has been sporadic, and the rocky core did not experience partial melting and igneous differentiation. On the other hand, the deduced pH is completely compatible with life as we know it; indeed, life on Earth may have begun under similar conditions, and terrestrial serpentinites support thriving microbial communities that are centered on H2 that is provided by water-rock reactions. These considerations provide major motivation for future missions to explore Enceladus as a habitable world, whether past or present.”

On Earth, soda lakes tend to be found in arid and semi-arid regions and in connection to tectonic rifts. Photosynthesis is the primary energy source for the lakes’ inhabitants, although deeper down, anoxygenic photosynthesizers and sulfur-reducing bacteria are also common. Similar kinds of non-carbon dioxide energy sources, including sulfur or nitrogen, would be required in oceans such as those in Enceladus or Europa, where no sunlight can reach the water below due to the surface ice crust.

Such a high-salinity ocean might not be the most ideal environment as far as life as we know it is concerned, but it is by no means a show-stopper, as the soda lakes on Earth have shown. If life ever started in the Enceladus ocean, there is seemingly no reason why it couldn’t have evolved and adapted to its environment. Cassini has already found organics in the watery plumes; could there be life itself? The only way to know will be to return to this moon with a spacecraft able to search for biomarkers in the plumes or even microorganisms themselves, which might get ejected out from the water below. Either would, of course, be a fantastic discovery.

The new paper, titled “The pH of Enceladus’ Ocean,” is available here, and more information about Cassini and Enceladus is here.

]]>http://themeridianijournal.com/2015/02/cassini-data-indicates-enceladus-ocean-similar-to-soda-lakes-on-earth/feed/0Blog update: WordPress problems and restorationhttp://themeridianijournal.com/2015/02/blog-update-wordpress-problems-and-restoration/
http://themeridianijournal.com/2015/02/blog-update-wordpress-problems-and-restoration/#commentsWed, 18 Feb 2015 03:15:01 +0000http://themeridianijournal.com/?p=5353After some technical problems with WordPress the past few days, the blog is now back online and basically restored, although unfortunately blog posts from about the past year have been lost. But at least it’s functioning again!

]]>After some technical problems with WordPress the past few days, the blog is now back online and basically restored, although unfortunately blog posts from about the past year have been lost. But at least it’s functioning again!

]]>http://themeridianijournal.com/2015/02/blog-update-wordpress-problems-and-restoration/feed/0About that ‘mystery rock’ on Mars: no it’s not a plant, but…http://themeridianijournal.com/2014/02/mystery-rock-mars-plant/
http://themeridianijournal.com/2014/02/mystery-rock-mars-plant/#commentsTue, 04 Feb 2014 04:19:37 +0000http://themeridianijournal.com/?p=5293There has been a lot of discussion the past few days about that lawsuit filed against NASA for supposedly covering up / failing to investigate evidence of life on Mars by the Opportunity rover. This all has to do of course with that “mystery rock” found by Opportunity, nicknamed Pinnacle Island, which somehow just appeared near the […]

There has been a lot of discussion the past few days about that lawsuit filed against NASA for supposedly covering up / failing to investigate evidence of life on Mars by the Opportunity rover. This all has to do of course with that “mystery rock” found by Opportunity, nicknamed Pinnacle Island, which somehow just appeared near the rover (most likely dislodged and kicked up by one of the wheels) a few weeks ago.

The lawsuit is frivolous for various reasons (as others have already adequately shown), including the fact that the rover has taken numerous Microscopic Imager images of the rock, contrary to what has been alleged. And the rock does look like just that, a rock, not a growing fungus or other plant, unfortunately.

That said, this brings up an interesting possibility which hasn’t been mentioned much yet. The rock, as NASA has said, appears to have been flipped upside down from its original position (and mission scientists are still looking for the spot where it came from). That underside has a dark reddish coating of some kind in the middle area which, as known so far from the analysis done, contains large amounts of sulfur, magnesium and even higher amounts of manganese. The outer edges have a whitish coating, which has been seen before on other Martian rocks (at least looks similar). Hence why the rock has also been called a “jelly doughnut” – white around the circumference and dark red in the middle.

The enigmatic Pinnacle Island rock, looking rather out of place against the blander background. Credit: NASA/JPL-Caltech/Stuart Atkinson

It is isn’t know yet just what the darker material is, but the unusually larger amounts of manganese in particular is interesting. On Earth, desert varnish also has unusually high concentrations of manganese in it. That is the dark coating which often form on rocks in desert environments. Could this be something similar? It may well not be, but it’s worth consideration. And while desert varnish still isn’t fully understood, it is thought to form with the assistance of microbes. Such a find on Mars would be most interesting.

One could speculate even further and say that the dark material could be a form of microbial mat or other very lowly form of life, previously protected on the once-hidden underside of the rock. Less likely perhaps, but not impossible. Another recent study on Earth again showed how some forms of fungus or lichen could easily survive Martian conditions.

So the mystery rock is not life itself, and is “just a rock,” but perhaps might still provide clues to what kind of life could have existed on Mars in the past or even still today. The mystery rock may be only a rock, but it might just be a very interesting one.

]]>http://themeridianijournal.com/2014/02/mystery-rock-mars-plant/feed/2Curiosity plays in a Martian sand dunehttp://themeridianijournal.com/2014/02/curiosity-plays-martian-sand-dune/
http://themeridianijournal.com/2014/02/curiosity-plays-martian-sand-dune/#commentsMon, 03 Feb 2014 03:22:38 +0000http://themeridianijournal.com/?p=5284Curiosity has also been taking a lot of close-up images of the sand dune which the rover has “toe-dipped” into. The rover’s wheels have left very distinct impressions in the very fine-grained sand within the dune, while the outside of the dune has a denser “crust” covered with many small rounded grains, similar to other […]

]]>Close-up view of the edge of a Curiosity wheel track in the sand dune at Dingo Gap. Click for larger version. Credit: NASA / JPL-Caltech

Curiosity has also been taking a lot of close-up images of the sand dune which the rover has “toe-dipped” into. The rover’s wheels have left very distinct impressions in the very fine-grained sand within the dune, while the outside of the dune has a denser “crust” covered with many small rounded grains, similar to other dunes seen by the Spirit and Opportunity rovers. Whether or not Curiosity will actually drive through the dune (if deemed safe) to the other side of Dingo Gap or just go around hasn’t been decided yet, but in the meantime there are lots of new images to enjoy.

Close-up view of Curiosity wheel tracks impressions in the sand with the dune. Very fine detail can be seen such as in the lower right portion of the image. Click for larger version. Credit: NASA / JPL-CaltechClose-up view of rounded grains on the surface of the sand dune. Click for larger version. Credit: NASA / JPL-Caltech

]]>http://themeridianijournal.com/2014/02/curiosity-plays-martian-sand-dune/feed/0Dingo Gap: new panorama and a rockhound’s bonanzahttp://themeridianijournal.com/2014/02/dingo-gap-new-panorama-rockhounds-bonanza/
http://themeridianijournal.com/2014/02/dingo-gap-new-panorama-rockhounds-bonanza/#commentsSun, 02 Feb 2014 04:13:52 +0000http://themeridianijournal.com/?p=5274Dingo Gap has turned out to be quite an interesting place for the Curiosity rover, being both scenic and of great geological interest. Rocks of all sizes and shapes litter the landscape amid the cliffs and sand dunes and Curiosity is continuing to study this area before driving further south toward Mount Sharp. Another new […]

Dingo Gap has turned out to be quite an interesting place for the Curiosity rover, being both scenic and of great geological interest. Rocks of all sizes and shapes litter the landscape amid the cliffs and sand dunes and Curiosity is continuing to study this area before driving further south toward Mount Sharp. Another new panorama by Damia Bouic shows the scenery in stunning high resolution and there is also a great overview by Emily Lakdawalla on The Planetary Society blog.

As is common in such landscapes, some of the rocks can take on curious shapes, such as the ones below, and of course the “firepit” mentioned previously. What story do they tell about the history of this area of Mars? The thin, flat, platy rocks look a lot like the shale outcrops seen previously at Shaler. Are they shale also or something different? The perfect place for a rockhound!

This rock kind of looks like a snail shell and the sharply pointed end is quite distinct from the rounded “ribbed” main body. Credit: NASA / JPL-CaltechContext image for “snail shell” rock. Click for larger version. Credit: NASA / JPL-CaltechThis one looks like a shield. Credit: NASA / JPL-CaltechContext image for “shield” rock. Click for larger version. Credit: NASA / JPL-CaltechThis boulder looks at first like a large rock sitting on a thin flat slab but on closer inspection appears to actually be all one formation. So how did it form? Credit: NASA / JPL-CaltechContext image for previous boulder/slab formation. Click for larger version. Credit: NASA / JPL-CaltechA partially buried wall? Looks like one, but more likely just an eroded edge of the small cliff. Click for larger version. Credit: NASA / JPL-Caltech